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Annotation of Gnu-Mach/i386/i386at/gpl/linux/include/asm/delay.h, revision 1.1.1.1

1.1       root        1: #ifndef _I386_DELAY_H
                      2: #define _I386_DELAY_H
                      3: 
                      4: /*
                      5:  * Copyright (C) 1993 Linus Torvalds
                      6:  *
                      7:  * Delay routines, using a pre-computed "loops_per_second" value.
                      8:  */
                      9:  
                     10: #ifdef __SMP__
                     11: #include <asm/smp.h>
                     12: #endif 
                     13: 
                     14: extern __inline__ void __delay(int loops)
                     15: {
                     16:        __asm__ __volatile__(
                     17:                ".align 2,0x90\n1:\tdecl %0\n\tjns 1b"
                     18:                :/* no outputs */
                     19:                :"a" (loops)
                     20:                :"ax");
                     21: }
                     22: 
                     23: /*
                     24:  * division by multiplication: you don't have to worry about
                     25:  * loss of precision.
                     26:  *
                     27:  * Use only for very small delays ( < 1 msec).  Should probably use a
                     28:  * lookup table, really, as the multiplications take much too long with
                     29:  * short delays.  This is a "reasonable" implementation, though (and the
                     30:  * first constant multiplications gets optimized away if the delay is
                     31:  * a constant)
                     32:  */
                     33: extern __inline__ void udelay(unsigned long usecs)
                     34: {
                     35:        usecs *= 0x000010c6;            /* 2**32 / 1000000 */
                     36:        __asm__("mull %0"
                     37:                :"=d" (usecs)
                     38: #ifdef __SMP__
                     39:                :"a" (usecs),"0" (cpu_data[smp_processor_id()].udelay_val)
                     40: #else
                     41:                :"a" (usecs),"0" (loops_per_sec)
                     42: #endif
                     43:                :"ax");
                     44:                
                     45:        __delay(usecs);
                     46: }
                     47: 
                     48: extern __inline__ unsigned long muldiv(unsigned long a, unsigned long b, unsigned long c)
                     49: {
                     50:        __asm__("mull %1 ; divl %2"
                     51:                :"=a" (a)
                     52:                :"d" (b),
                     53:                 "r" (c),
                     54:                 "0" (a)
                     55:                :"dx");
                     56:        return a;
                     57: }
                     58: 
                     59: #endif /* defined(_I386_DELAY_H) */

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